[Pharmacokinetic behavior of pefloxacin in man]

The pharmacokinetic profile of pefloxacin is one of the major assets of this new antibiotic of the quinolone family. Digestive absorption is rapid and complete after oral administration. The pharmacokinetic pattern is the same with both routes. The high apparent volume of distribution (AVD = 117 +/- 6 litres) reflects good diffusion in extravascular compartments. Pefloxacin can therefore be used not only for the treatment of systemic infections, but also for that of extravascular infections, whatever the perfusion rate of the infected organ. The predominant route of excretion of pefloxacin is extrarenal, after hepatic degradation; it is responsible for prolonged elimination half-life in patients with hepatic insufficiency. Since renal excretion of the unchanged drug is less important, there is no need to modify the dosage in case of renal impairment. When pefloxacin is eliminated by biotransformation, it is excreted slowly, and plasma or tissue levels of its unchanged form remain much higher. In subjects with normal liver function, the mean elimination half-life is almost 12 h, which makes it possible to administer pefloxacin twice a day. During treatment with 400 mg doses, the steady state is reached within 48 h; mean peak plasma concentrations then are 10 micrograms X ml-1 and mean trough concentrations 4 micrograms X ml-1. The pharmacokinetic properties of pefloxacin give this antibiotic an unquestionable advantage over third-generation cephalosporins and aminoglycosides.